1. Field of the Disclosure
This disclosure relates to an apparatus and method for forging/extruding a shaped component, for example a shaped component of a gas turbine engine. At least part of the disclosure relates to a method and apparatus for use in automated forging/extruding of a shaped component.
2. Description of the Related Art
Forging is used in a variety of metalworking operations in order to produce shaped components. Typically, a hammer or ram is used to provide a compressive force to a billet of metal (which may be heated) in order to deform the metal into the shape of a die.
Various different types of forging process have been developed to suit the desired properties of the shaped component, for example in terms of size, shape, material properties and required throughput.
In one particular type of forging, which may be referred to as a horizontal split die forging press or as a multiforge, a billet of heated metal is positioned in a forging press, and then a ram is used to strike the billet so as to provide a, typically horizontal, force to press the metal billet into a die. In this way, the shape of the billet deforms so as to take on the shape of the die. Such an arrangement may be suitable for automation, for example using an reciprocating ram and an automated machine for positioning the billet and removing the shaped part from the die.
An example of a forging apparatus 100 is shown in FIG. 1. The forging apparatus 100 comprises an upper press 110 and a lower press 120. In operation, the upper press 110 and the lower press 120 move together and are held together by a grip load, which may be on the order of hundreds of tonnes. A die piece 130 is positioned between the upper press 110 and lower press 120. The die piece 130 holds a billet of metal 150 when the presses 110, 120 are moved together under the grip load.
In the forging operation, a punch 140 is propelled towards the billet 150 in a direction shown by arrow A in FIG. 1. The punch 140 comprises a ram portion 144 and a striking portion 142. The striking portion 142 strikes the billet 150, which may be pre-heated, and forces the metal in the billet 150 to move in the general direction of arrow A into a shaped die 132, which is a part of the die piece 130. In this way, the shape of the billet 150 changes to correspond to the shape of the shaped portion 132.
FIG. 2 shows a cross section through a part of the forging apparatus 100 after extrusion of the original billet 150 has taken place. Accordingly, the original billet 150 has been deformed into the forged part 155, at least a part of which corresponds to the shaped portion 132 of the die piece 130. In FIG. 2, the upper press 110 is shown as being provided with a shaped portion 112 (which may be in the form of an upper die piece), and the shape of the forged part 155 also corresponds at least in part to the shape of the shaped portion 112 of the upper press 110.
After the forging has taken place by striking the billet 150 with the striking portion 142 in the direction of arrow A shown in FIG. 1, the grip load is released and the upper press 110 is moved away from the rest of the apparatus in the direction of arrow C, shown in FIG. 2. Due to the high energy involved in the extrusion process (which may lead to a degree of distortion of the punch 140 and/or the die piece 130 and/or the upper press 110 and/or lower press 120), the forged part 155 may on some occasions stick to the upper press 110 at the interface 160 as it is moved away in the direction of arrow C, and thus may be lifted away from the die piece 130. On other occasions, the forged part may remain in the die piece 130. It can be unpredictable whether or not the forged part 155 will remain in the die piece 130 on any given extrusion cycle. Where the forged part 155 is lifted up with the upper press 110, it may or may not stay attached to the upper press 110. On occasions where the forged part 155 is lifted up with the upper press 110 and then subsequently falls away (for example due to relative expansion/contraction resulting from temperature changes), the final position of the forged part may be entirely unpredictable.
If the forging apparatus 100 is being operated manually, then this unpredictability of the position of the forged part 155 after the forging process may result in an increase in overall process time as the operator has to locate the forged part 155, and in some cases remove it from the upper press 110 (which may not be straightforward), before transferring, it to the next step of the manufacturing process.
However, an even greater problem occurs where the forging process is automated and/or where it is part of an automated manufacturing process. For example, an automated process may require the use of a machine (such as a robot) to transfer the forged part 155 to another apparatus for further processing, such as machining and/or clipping. In order for this to be possible, it is necessary for each forged part 155 to be in the same position after every forging cycle, i.e. after the upper press 110 has been moved away from the lower press 120. If the position of the forged part 155 may be different for each forging cycle, as may occur with the conventional apparatus/Process described above, then the robot that is used to transfer the forged part 155 to the next step of the process will not be able to reliably locate the part 155, and the automated process would fail.